Attachment of a floor structure to an aircraft fuselage requires distribution of the loads from the floor into the fuselage structure, must provide adequate equalization venting between the passenger compartment and the cargo bay in the event of rapid decompression in either of the compartments, and must maintain structural integrity at this interface in the event of shear loading induced by rapid or instant deceleration. Typical metallic aircraft utilize rigid floor beams attached directly to fuselage hoop frames to carry vertical floor loads and rely on a horizontally planar shear truss attached between the floor and the side walls of the fuselage to contain shear loads during rapid deceleration. This truss also may contain cutout apertures for the equalization venting.
Composite honeycomb floors are self-stiffened structures that may not require floor beams when sufficiently thickened and therefore, may not be directly coupled to the fuselage walls. Instead, upper support stanchions may be provided to support the floor. While they may provide vertical support for the floor, the stanchions may have the potential to induce a cantilevered load condition between the floor and the fuselage sidewall since the floor may not extend completely to the fuselage sidewall. With emerging composite technologies using honeycomb structures for airframes and passenger floors, there demands new innovative methods to accommodate the design requirements imposed on the floor to fuselage structural interface since honeycomb fuselage barrels do not have hoop frames and the composite floors may not have support beams underneath that connect to the fuselage sidewall.